On Sale: Thompson & Morgan worker Michael Perry with the TomTato plant sold by his company

With tomatoes at one end and potatoes at the other, it looks like the product of some Frankenstein food laboratory. But far from being the latest genetically modified monster, this horticultural wonder is entirely natural. Called the TomTato, each plant can yield more than 500 sweet cherry tomatoes as well as a decent crop of white potatoes.

It is produced using a hi-tech grafting process and was unveiled to the public yesterday before going on sale to gardeners in the UK for the first time.The project took a lot longer to bear fruit than the plant does, however.

It began 15 years ago when Paul Hansord, horticultural director of mail order gardening company Thompson & Morgan, was on a trip to the US. He spotted a potato plant growing separately under a tomato plant and learned that it is possible to graft the two together because they belong to the same family.

Hybrid: The ‘TomTato’ plant produces cherry tomatoes from its stem and potatoes from its roots

His problem was how to develop the idea so the plants could be sold commercially. The stumbling block had been how to produce tiny potato plants which have stems the same thickness as seedling tomatoes, so that the two can be joined together perfectly. But after a process of trial and error, and with the help of grafting specialists, Thompson & Morgan hit upon a method using a variety of potato that produces the right size shoot.

Careful variations in the temperature at which the tomato and potato are initially grown are also made to ensure the two plants are a perfect match before being joined together.

‘At the start, we thought it’d just be a novelty thing to do. But as the trials developed we realised what we had produced was really high yield, had fantastic flavour and could be done commercially for the first time,’ Mr Hansord said yesterday.